Tape storage systems are typically used to store backup data of one or more computer systems. A tape storage system can be connected directly to a computer system, or the tape storage system can be part of a storage area network accessible by a plurality of computer systems.
A tape storage system typically includes multiple tape cartridges that are selectively picked for loading into a tape drive of the tape storage system. The picking of a tape cartridge is accomplished by use of a picker assembly (also referred to as a robot). In some tape storage systems, the tape cartridges are arranged on a movable platform, such as a conveyor platform, to allow the tape cartridges to move relative to the picker assembly. Once a desired one of the tape cartridges is moved proximal the picker assembly, the tape cartridge is grabbed by the picker assembly. The picker assembly then rotates to a position to enable the loading of the picked tape cartridge into a tape drive.
A picker assembly usually selects a tape cartridge in the tape storage system by reading labels on the tape cartridges. In one implementation, each label contains a bar code. The picker assembly includes a reader, such as a bar code reader, to read the label of each tape cartridge. The bar code reader receives light reflected from the bar code of a tape cartridge to determine the identifier of the tape cartridge. Conventionally, the bar code reader reads the bar code along a direction that is perpendicular to the bars of the bar code. In other words, the bar code reader receives light reflected from the bar code along a direction that is parallel to an axis defined along the width of the bar code.
If the bar code reader and tape cartridge label are moveable with respect to each other only along the axis defined along the width of the bar code, then the bar code reader may not be able to read a different part of the bar code in case a first read fails. A bar code reader may thus not be able to successfully read a bar code if there is some irregularity on the bar code, such as due to a portion of the bar code being removed or damaged, that prevents the bar code reader from reading the entire bar code. The inability to read a bar code may lead to errors in accessing data stored in a tape storage system.